| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical fiber for amplification capable of optically amplifying light to be amplified with a high gain while suppressing generation of ASE light. SOLUTION: This optical fiber for amplification includes a core region 10 to which an optical active element having a gain in a prescribed wavelength band is added, and a clad region 20 surrounding the core region 10, a refractive index distribution on the cross section of the clad region 20 perpendicular to a fiber axis has a two dimensional periodic structure, and a core region 10 is formed by a defect in the center of the two dimensional cycle structure. The optical fiber for amplification has a transmission band and a cut-off band originated in the two dimensional periodic structure of the refractive index distribution on the cross section of the clad region 20, has a loss larger than a gain by the core region 10 to which the optical active element is added in a band where a part of a prescribed wavelength band overlaps with the cut-off band, and has a loss smaller than a gain by the core region 10 to which the optical active element is added in a band where other parts of the prescribed wavelength band overlaps with the transmission band. COPYRIGHT: (C)2009,JPO&INPIT |
